I have two thoughts that may be related:
1. When it comes to I&B, the genie never gets put back in the bottle, so forget about shrinking courses.
2. Given the collapse in demand - well, a reduction at least - among the next generation of golfers, as the average age of a club's / course's golfers rises, back tees will atrophy and the length played by most will drop well below 6,500. Hmm, I wonder if course maintenance /architecture conflicts between older and younger members will be the spiritual descendent of golfer vs tennis player budget battles.
And one more thought:
Forget about shorter and focus on wider. Many courses are too narrow for their length. Some have been made that way via narrowed fairways.